It is known to use long time interleaving (LTI), forward error correction (FEC) and/or Direct, or Zero-IF (ZIF) tuners in satellite radios to assist in providing a quality satellite radio operating performance, which includes audio frequency performance as heard by an ear of a human operator of the satellite radio.
One task of the FEC is to assist and allow a satellite radio to recover originally transmitted satellite RF signal data with a minimum number of bit errors. Another task of a FEC may be to correct bit errors caused by channel noise or missing satellite radio frequency (RF) signal transmissions. Mathematical algorithms in the FEC often employ averaging techniques on the satellite RF signal energy over the FEC block length to provide channel noise correction. Another FEC algorithm technique may average strong RF signals to correct when RF signals are not received by the satellite receiver. Thus, the FEC assists to ensure the operator of the satellite radio has listenable subject content that might not otherwise be available. Such a scenario may occur, for example, when the operator's vehicle that includes the satellite radio enters a tunnel. One type of tunnel is experienced by the operator when the vehicle travels on a road that passes under a road overpass. When the vehicle is located in the tunnel, especially a tunnel that has an extended depth, weak satellite RF signal reception by the satellite receiver may negatively degrade, or diminish the operator's audio listening performance of the satellite radio. It is desired to further maximize satellite receiver long time interleaver performance for extended tunnel depths. Additionally, ZIF tuners are increasing being utilized in satellite radios that result in lower manufacturing costs, as the typical SAW filter previously employed is advantageously eliminated from the satellite radio circuitry. One drawback of the zero-IF tuner, however, is an increase in DC offset noise that may occur when a local oscillator (LO) signal undesirably leaks into a signal path of the satellite receiver and is subsequently frequency down-converted to baseband, or zero volts DC. Increased DC offset noise may result in an increased number of undesired listenable audio frequency interruptions, such as audio mutes, that may be heard in the listenable audio stream by the operator. As the commercial popularity of satellite radio remains constant, or even grows with consumers in the marketplace, it remains desirable to further enhance satellite radio performance wherever the satellite radio, or receiver is operated.
Thus, what is needed is a robust satellite receiver that further enhances the long time interleaver and listenable audio frequency performance for an operator of the satellite receiver. These enhancements include, but are not limited to, having enhanced long time interleaver performance when traveling through a tunnel, ensuring enhanced weak-to-strong received satellite RF signal performance using Reed-Solomon (RS) codeword error checking that prevents erroneous baseband signal data from being accepted as good baseband signal data, and eliminating DC offset noise in a satellite receiver that has a ZIF tuner.